perplexus.info :: Numbers : Duplicate Digit Determination

Duplicate Digit Determination (Posted on 2006-12-03)

If 2^P and 5^P start with the same (non-zero) digit for positive integer P, what is that digit? Can you prove it must be so?

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Some calculations (spoiler)

| Comment 2 of 6 |

Removed my comments, which were slightly wrong. I like Charlie's explanation better, anyhow.

Edited on December 3, 2006, 11:12 am

Posted by Steve Herman on 2006-12-03 11:08:27

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